1. Field of the Invention:
The present invention relates to a fluid jet loom equipped with a picking device including a main picking nozzle and a plurality of groups of auxiliary nozzles and, more specifically, to a faulty picking diagnosing system capable of diagnosing a faulty picking operation through the measurement of the actual weft yarn unwinding time, the actual weft yarn arrival time and, when necessary, the flow rate of the picking fluid, and comparison of the measured results with the corresponding target values.
2. Prior Art:
The fluid jet loom uses a jet of air or water for picking a weft yarn. Faulty picking results from inappropriate jet stating time, inappropriate jet ending time and/or inappropriate pressure of the picking fluid or from unsynchronized weft yarn unwinding and picking fluid jetting.
Japanese Patent Laid-open Publication No. 60-110,952 discloses an invention which measures the weft yarn arrival time at a position in the path of the weft yarn, compares the measured weft yarn arrival time with a target weft yarn arrival time, and regulates the pressure of the picking fluid on the basis of the result of the comparison so that correct picking operation is achieved. However, since the faulty picking operation is not diagnosed, it is possible that the faulty picking operation occures again after the correction of the pressure of the picking fluid.
Generally, it has been a conventional practice to determine the cause of faulty picking operation through the visual inspection of picking condition by the operator, in which the causes of faulty picking operation are classified roughly into short pick, yarn end breakage, faulty shedding, bent pick, and weft breakage. Accordingly, it has been fifficult to find the exact cause of faulty picking operation through the visual inspection of the picking condition by the operator. This difficulty has been a significant obstacle to the stable operation of the loom. It is essential, particularly in a weaving mill equipped with many looms, to the enhancement of productivity and the improvement of the quality of fabrics to find the exact cause of faulty picking operation quickly and to correct the cause rapidly.